Add helix keyboard (#2308)

* Fork from Let's Split

* Organizing files

* Delete some keymaps

* I2C and serial enabled at the same time

* Change readme

* add #define HELIX_ROWS for multiple rows

* Delete avrdude flashing script

* Delete makefiles

* Subproject elimination

* Fix lufa path

* Remove PLAY_NOTE_ARRAY usages to get rid of warning.

Fix conflicting function name

* Mousekey change default to off

* Fix to oled display adjust

* make rev2

change pin assign
change keymap

* use master_buffer

* Timing adjustment

* Organizing files

* Change Keymap

* Change Keymap

Add EISU and KANA
Correct 4rows

* NKRO default to disable

* EXTRAKEY_ENABLE default to disable

* add rgb reset key

* rgb custom function enable

*  Extend font

* add RGBLED_POWER

default folder to helix/rev2
RGB_ENABLE to no

* renamed directory

* Disable RGBLIGHT_CUSTOM_DRIVER

* Disable LOCKING_SUPPORT_ENABLE

* Update bootloader setting

* Change readme

* Fixed argument error

1 files changed, 49 insertions, 0 deletions

diff --git a/keyboards/helix/i2c.h b/keyboards/helix/i2c.h
new file mode 100644
index 000000000..c15b6bc50
--- /dev/null
+++ b/keyboards/helix/i2c.h
@@ -0,0 +1,49 @@
+#ifndef I2C_H
+#define I2C_H
+
+#include <stdint.h>
+
+#ifndef F_CPU
+#define F_CPU 16000000UL
+#endif
+
+#define I2C_READ 1
+#define I2C_WRITE 0
+
+#define I2C_ACK 1
+#define I2C_NACK 0
+
+#define SLAVE_BUFFER_SIZE 0x10
+
+// i2c SCL clock frequency
+#define SCL_CLOCK  400000L
+
+extern volatile uint8_t i2c_slave_buffer[SLAVE_BUFFER_SIZE];
+
+void i2c_master_init(void);
+uint8_t i2c_master_start(uint8_t address);
+void i2c_master_stop(void);
+uint8_t i2c_master_write(uint8_t data);
+uint8_t i2c_master_read(int);
+void i2c_reset_state(void);
+void i2c_slave_init(uint8_t address);
+
+
+static inline unsigned char i2c_start_read(unsigned char addr) {
+  return i2c_master_start((addr << 1) | I2C_READ);
+}
+
+static inline unsigned char i2c_start_write(unsigned char addr) {
+  return i2c_master_start((addr << 1) | I2C_WRITE);
+}
+
+// from SSD1306 scrips
+extern unsigned char i2c_rep_start(unsigned char addr);
+extern void i2c_start_wait(unsigned char addr);
+extern unsigned char i2c_readAck(void);
+extern unsigned char i2c_readNak(void);
+extern unsigned char i2c_read(unsigned char ack);
+
+#define i2c_read(ack)  (ack) ? i2c_readAck() : i2c_readNak();
+
+#endif